The present invention relates to an equalizing circuit for reducing surface roughness of an image and a method thereof, and an image processing circuit and a method by the use of the equalizing circuit and its method.
Conventionally, for example, Jpn. Pat. Appln Publication No. 8-18777 discloses an art with respect to an image processing unit, which improves a resolution of a character part of an image represented by the input image data and improves a gradation of a picture part thereof. That is, according to this art, a character region and a photographic region of an original document are separated and a region signal is output. Then, in accordance with this region signal, gradation processing results for a character and a photograph are selectively switched.
However, in the above described conventional art, it is not suggested to equalize the image signals of the original document in increments of an arbitrary block from an arbitrary position. Further, it is not specifically disclosed to reduce the surface roughness of the image.